An HM1.24 is a type II transmembrane glycoprotein identified as a myeloma-specific antigen, and is expected to be a target molecule in the immunotherapy of multiple myeloma as well as other cancers where the tumour cells express HM1.24 antigen. In order to generate a protective anti-tumour response, an efficient presentation of an appropriate cancer antigen is required. A dendritic cell is one of the most efficient antigen-presenting cells, capable of priming a naive T cell, and inducing both a CD4 T helper cell response and a CD8 cytotoxic T cell response. Hence dendritic cells are ideal antigen-presenting cells for use in cancer immunotherapy. However, it has not become possible that a dendritic cell is employed as an antigen-presenting cell for an HM1.24 antigen to stimulate a T cell whereby generating a cytotoxic T cell and exerting damage on a cancer cell.